Cushioned dock fender structure and shear type cushion member

ABSTRACT

A dock fender structure for cushioning the impact of vessels thereagainst by the deflection in shear of elastomeric cushion members, and a cushion member adapted for use therein.

United States Patent [191 Shirvany CUSHIONED DOCK FENDER STRUCTURE AND SHEAR TYPE CUSHION MEMBER [75] Inventor: John Anoush Shirvany,Simi,Calif.

[73] Assignee: Byron Jackson Inc., Long Beach,

Calif.

Filed: Sept. 8, 1971 Appl. No.: 178,589

US. Cl. 61/46, 61/48 Int. Cl E02b 3/22 Field of Search 61/48, 46; 114/219;

References Cited UNITED STATES PATENTS 3/1972 Gensheimer 61/48 Oct. 9, 1973 Wanneroy 61 /46 De Ment 267/140 X Miura 61/48 Slemmons..... 61/48 Wanneroy 61/48 Primary Examiner-Mervin Stein Assistant ExaminerDavid H. Corbin Att0rney-Donald W. Banner et al.

ABSTRACT A dock fender structure for cushioning the impact of vessels thereagainst by the deflection in shear of elastomeric cushion members, and a cushion member adapted for use therein.

2 Claims, 6 Drawing Figures PAIENIED 3.763.653

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CUSHIONED DOCK FENDER STRUCTURE AND SHEAR TYPE CUSHION MEMBER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to cushioned .dock fender structures and to shear-type cushion elements or members especially adapted for use therein.

2. Description of the Prior Art Heretofore, cushioned dock fender structures have been provided for cushioning the impacts and movements of vessels moored to a wharf. One such structure, the buckling-column type, is disclosed in US. Pat. No. 3,172,268, issued Mar. 9, 1965. Another, which employs cushionmembers that function in shear, compression, and/r tension, is disclosed in U.S. Pat. No. 3,457,729, issued July 29, 1969.

SUMMARY OF THE INVENTION An object of the present ivnention is to provide a cushioned dock fender structure incorporating cushion members that function substantially only in shear; hence, the cushion members are not subject to tensile and compressive forces that might overstress them.

A further object is to provide cushion elements, particularly for use in such dock fender structure, that are rugged and relatively simple to manufacture, and that give long and reliable service. I

The foregoing and other aims, objects and advantages of theinvention are realized in a cushioned dock fender structure and the like including: a stationary member; a movable member comprising piling driven into mud adjacent to and spaced from the stationary member, the movable member being positioned to be struck by a craft adjacent to the structure; and-energyabsorbing meansconnectedbetween said members for dissipating energy imparted to the movable member upon being struck by a craft, said energy-absorbing meansincluding a block of elastomeric material, first means mountingsaid block to one of the members, and second means mounting the block to the other of the members, the blockbeing mounted to deflect in shear for cushioning the horizontal movements of the movable member and to be substantially free from compression and tension stresses when it is substantially neutral in shear, the first means and the second means each comprising a metallplate having a central portion embedded in andbonded to the block, and having marginal portions projecting from opposite sides of the block, the centralportion having holes through which portions of the block'extend from one face of the plate to the other face, and means securing the marginal portions of 'theplate to a respective one of the members.

The energy-absorbing means or cushion member of the invention includes: a block. of elastomeric material, each end of the'block having embedded therein and bonded, preferably chemically bonded, thereto the central portion of a metalplate having marginal portions projecting from opposite sides of the block, the central portion having holes through which portionsof the block. extendfrom oneface of the plate tothe other face, the marginal portions being adapted for securement of the assembly in shear to a pair of relatively movable members of .a dock fender structure and the like.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawing, in which like reference numerals designate like parts in the several views,

FIG. 1 is a side view of a preferred form of dock fender structure embodying the invention;

FIG. 2 is a plan view of a portion of the dock fender structure shown in FIG. 1, showing a portion in section;

FIG. 3 is a view similar to FIG. 1 showing parts of the dock fender structure displaced into alternative operative position;

FIG. 4 is a plan view on an enlarged scale of an energy-absorbing subassembly incorporated in the dock fender structure shown in FIGS. 1 to 3;

FIG. 5 is a view taken along the line 5-5 of FIG. 4 and looking in the direction of the arrows; and

FIG. 6 is a view taken along the line 6-6 of FIG. 5 and looking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, especially to FIGS. 1 and 2 thereof, the cushioned dock fender structure shown includes a stationary pier or wharf 10, to which boats or vessels (not shown) in the waterway or slip 11 are moored, as for taking on or discharging cargo. Vertical piles 12, specifically I-beams, are arranged in a row parallel to the face 13 of the pier, the piles being driven into the mud at the bottom of the waterway ll. Horizontal timbers 14 are fastened to the front faces of the piles l2 and are arranged in vertically spaced disposition above the waterway 11 to form a vertical pad against which the side of a vessel can strike or ride when the vessel is moored to the pier. Each pile 1.2, or selected ones of them, has a pair of vertically spaced, cantilever beams 15 and 16 welded to it and projecting horizontally toward the pier 10. This pair of beams is positioned at about the level of the timbers 14. A third cantilever beam 17 is fastened, as by lag screws 18, to the pier 10; this beam extends horizontally towards the pile l2 and into the vertical gap between the beams 15 and 16.

An upper cushion member 19 is interposed between the top of the beam 17 and the bottom of the beam and is secured to the respective beams by suitable fasteners, such as screws 21 and 22. An identical lower cushion member 19a is similarly secured to the bottom of the beam 17 and the top of the beam 16. These cushion members are energy-absorbing subassemblies that willbe described in greater detail hereinafter. In brief,

however, each cushion member consists of a block of elastomeric material 23, typically rubber, affixed at its opposite ends to a steel-top plate 24 and asteel bottom plate 25, by means of which plates the cushion member is secured to the cantilever beams.

The manner in which the fender structure of the inventionoperates will now be described with particular reference to FIGS. 1 and 3. When a boat in the waterway 1 1 moves against or strikes the pad provided by the timbers 14, the piles 12 with their beams 15 and 16 move inwardly towards the pier 10 from the positions shown in FIG. 1 to the positions shown in FIG. 2. In so moving, the beams 15 and 16 carry the upper end of the cushion member 19 and the lower end of the cushion member inwardly towards thepier 10,.thereby deflecting the elastomeric blocks 23 in shear and absorbing in the blocks energy imparted to the fender structure by the impact of the boat against the timber pad. The energy stored in the blocks 23 tends to return the system to the neutral condition illustrated in FIG. 1. Of course, there may be some oscillation of the piles l2 and the components carried thereby before their rest positions are reached.

Turning now to FIGS. 4 to 6, there is shown therein a preferred form of cushion member 19 as used in the fender structure of FIGS. 1 to 3. The top and bottom plates 24 and 25 are of identical form. Each plate is rectangular in plan view and has a recessed central portion 26 embedded in the rubber block 23 and marginal portions or cars 27,27 projecting from opposite sides of the rubber block. These ears are horizontal and extend in the direction in which the rubber block is deflected in operation of the fender structure into which the cushion member is incorporated. The ears 27,27 have screw holes 28,28 through which the screw fasteners 21,21 pass (see FIG. 1) to secure the cushion member to the cantilever beams 17,15 or 17,16. The central portion 26 of the plate has a number of openings 29,29 at the sides of the plate and a larger opening 31 in the center of the plate. The block 23 has a cylindrical hole 32 extending through it in the direction in which the block is deflected in use.

The cushion member 19 is formed by conventional rubber molding techniques using heat and pressure. In the molding operation, rubberfrom part of the block 23 between the plates is extended through the holes 29,29 and 31 in the top and bottom plates and around the lateral edges of the plates to completely surround the central portion 26 of the plate and embed it in the rubber. The connecting portions of rubber that extend through the holes 29,29 and 31, and around the lateral edges of the plate unite the portion of the rubber block between the plates with thin rubber portions 33 and 34 at the top and bottom, respectively, of the cushion member. Thus, the plates 24 and 25 are securely attached to the rubber block 23 by mechanical envelopment of the central portions of the plates by the upper and lower portions of the rubber block. In addition, the tenacity of attachment of the central portions of the plates to the rubber block is greatly enhanced by coating the central portions of the plates with a chemical bonding cement before molding and curing the cushion member. Such chemical bonding cements are well known in the art of rubber-to-metal bonding. Thus, the plates may be said to be chemically and mechanically bonded to the rubber block.

A cylindrical hole 32 preferably is provided and may be formed through the rubber block 23 by a core placed in the mold during the molding of the cushion member. This cylindrical hole gives the cushion member a lower R/E ratio than a smaller size, solid cushion member having an equivalent energy absorption; in the expression R/E, R is the force from the impact to deflect the cushion member in shear through a distance, and E is the energy absorbed by the cushion member when so deflected. It is noted, however, that the hole 32 is not essential, and that, if employed, it may be oriented in the rubber block 23 in a direction other than that shown in the drawings.

FIG. 1 shows the cushioned dock fender structure in the neutral condition. In an ideal structure, the positions of the cantilever beams 15, 16 and 17 are so chosen with regard to the height of the cushion members l9 and 19a that these cushion members have no substantial vertical compressive or tensile forces applied to them when they are in the neutral condition shown in FIG. 1. The beams 15 and 16 are supported by the pile 12 in such a way that they are maintained at substantially the same distances from the fixed beam 17 throughout the range of deflection of the beams 15 and 16 towards and away from the pier 10. Therefore, there is no substantial vertical movement of the beams 15 and 16 with respect to the beam 17. Hence the only substantial forces applied to the cushion members 19 and 19a during functioning of the fender structure are those imposed by relative parallel movement of the beams 15 and 16 towards and away from the pier 10. Expressed in another way, no vertical loads are applied to the cusion members by relative vertical movements of the beams as the cushion members are deflected in shear. The piles 12, being firmly anchored in the bottom against vertical movements, may be said to support the movable beams 15 and 16 of the fender structure for substantially solely horizontal movements towards and away from the pier. Other support structure for substantially preventing vertical movements of the beams 15 and 16 may, of course, be provided in lieu of the piles 12. Moreover, the piles 12 will not move vertically with the rise and fall of a boat moored against the timbers 14, as the sides of the boat will simply slide over the pad formed by the timbers. Therefore the beams 15 and 16 do not transmit to the cushion members forces engendered by the rise and fall of the boat.

As a practical matter, however, oblique impacts against the cushioned dock fender structure of this invention will result in minor deviations from the ideal. Thus, depending upon the angle of impact, small deflections of the cushion members in the vertical or horizontal directions, taken with reference to the drawings, may occur, in addition to the principal deflection of the cushion members in shear. Therefore, the expression to deflect in shear is used herein in a broad sense and is not limited to the ideal of percent deflection in shear, but includes also the foregoing small deflection of the cushion members that may occur in addition to the principal or main deflection in shear.

From the foregoing description of the preferred embodiment, it will be seen that the invention provides a cushioned dock fender structure that subjects the cushion members embodied in it to deflections substantially limited to deflections in shear. The invention also provides cushion members uniquely capable of efficient operation and having long service life when deflected in shear. Although but one illustrative embodiment of the invention is shown and described herein, the invention is not to be considered as limited to this embodiment but is to be construed as broadly as the prior art will permit.

I claim:

1. A cushioned dock fender structure and the like comprising: a stationary member; a movable member comprising piling driven into mud adjacent to and spaced from said stationary member, said movable being positioned to be struck by a craft adjacent to the structure; and energy-absorbing means connected between said members for dissipating energy imparted to said movable member upon being struck by said craft; said energy-absorbing means comprising a pair of spaced cantilevered beams carried by one of said members and projecting towards the other of said members, a single cantilevered beam carried by the other of said members and projecting reciprocably between said pair of beams, a first block of elastomeric material mounted to deflect in shear between said single beam and one of said pair of beams, and a second block of elastomeric material mounted to deflect in shear between said single beam and the other of said pair of beams, means for mounting each of said elastomeric blocks to its respective beams including a metal plate adjacent to each end of each block, each metal plate having a recessed central portion embedded in and bonded to the block, and having marginal portions free of elastomeric material projecting from opposite sides of the block, said central portion having holes through which portions of the block extend from one face of the plate to the other face, and means for securing said marginal portions to the respective beams.

2. A cushioned dock fender structure and the like as defined in claim 1, wherein the central portion of each plate is substantially coextensive with the portion of the block in which it is embedded.

a: a: r 

1. A cushioned dock fender structure and the like comprising: a stationary member; a movable member comprising piling driven into mud adjacent to and spaced from said stationary member, said movable being positioned to be struck by a craft adjacent to the structure; and energy-absorbing means connected between said members for dissipating energy imparted to said movable member upon being struck by said craft; said energy-absorbing means comprising a pair of spaced cantilevered beams carried by one of said members and projecting towards the other of said members, a single cantilevered beam carried by the other of said members and projecting reciprocably between said pair of beams, a first block of elastomeric material mounted to deflect in shear between said single beam and one of said pair of beams, and a second block of elastomeric material mounted to deflect in shear between said single beam and the other of said pair of beams, means for mounting each of said elastomeric blocks to its respective beams including a metal plate adjacent to each end of each block, each metal plate having a recessed central portion embedded in and bonded to the block, and having marginal portions free of elastomeric material projecting from opposite sides of the block, said central portion having holes through which portions of the block extend from one face of the plate to the other face, and means for securing said marginal portions to the respective beams.
 2. A cushioned dock fender structure and the like as defined in claim 1, wherein the central portion of each plate is substantially coextensive with the portion of the block in which it is embedded. 